ClickHouse

Golang SQL database driver for Yandex ClickHouse. Supported by Kinescope.

Key features

• Uses native ClickHouse TCP client-server protocol
• Compatibility with database/sql (slower than native interface!)
• Marshal rows into structs (ScanStruct, Select)
• Unmarshal struct to row (AppendStruct)
• Connection pool
• Failover and load balancing
• Bulk write support (for database/sql use begin->prepare->(in loop exec)->commit)
• AsyncInsert
• Named and numeric placeholders support
• LZ4 compression support
• External data

Support for the ClickHouse protocol advanced features using Context:

• Query ID
• Quota Key
• Settings
• OpenTelemetry
• Execution events:
  • Logs
  • Progress
  • Profile info
  • Profile events

database/sql interface

OpenDB

conn := clickhouse.OpenDB(&clickhouse.Options{
	Addr: []string{"127.0.0.1:9999"},
	Auth: clickhouse.Auth{
		Database: "default",
		Username: "default",
		Password: "",
	},
	TLS: &tls.Config{
		InsecureSkipVerify: true,
	},
	Settings: clickhouse.Settings{
		"max_execution_time": 60,
	},
	DialTimeout: 5 * time.Second,
	Compression: &clickhouse.Compression{
		clickhouse.CompressionLZ4,
	},
	Debug: true,
})
conn.SetMaxIdleConns(5)
conn.SetMaxOpenConns(10)
conn.SetConnMaxLifetime(time.Hour)

DSN

• hosts - comma-separated list of single address hosts for load-balancing and failover
• username/password - auth credentials
• database - select the current default database
• dial_timeout - a duration string is a possibly signed sequence of decimal numbers, each with optional fraction and a unit suffix such as "300ms", "1s". Valid time units are "ms", "s", "m".
• connection_open_strategy - random/in_order (default random).
  • round-robin - choose a round-robin server from the set
  • in_order - first live server is chosen in specified order
• debug - enable debug output (boolean value)
• compress - enable lz4 compression (boolean value)

SSL/TLS parameters:

• secure - establish secure connection (default is false)
• skip_verify - skip certificate verification (default is false)

Example:

clickhouse://username:password@host1:9000,host2:9000/database?dial_timeout=200ms&max_execution_time=60

Benchmark

V1 (READ)	V2 (READ) std	V2 (READ) native
1.218s	924.390ms	675.721ms

V1 (WRITE)	V2 (WRITE) std	V2 (WRITE) native	V2 (WRITE) by column
1.899s	1.177s	699.203ms	661.973ms

Install

go get -u github.com/ClickHouse/clickhouse-go/v2

Examples

native interface

• batch
• async insert
• batch struct
• columnar
• scan struct
• bind params

std database/sql interface

• batch
• async insert
• open db
• bind params

Alternatives

• Database drivers

  • mailru/go-clickhouse (uses the HTTP protocol)
  • uptrace/go-clickhouse (uses the native TCP protocol with database/sql-like API)
  • drivers with columnar interface :
    • vahid-sohrabloo/chconn
    • go-faster/ch

• Insert collectors:

  • KittenHouse
  • nikepan/clickhouse-bulk

Useful projects

• clickhouse-backup
• go-graphite